This application claims the priority of European application No. 97 119 483.2, filed Nov. 7, 1997, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a method and apparatus for stabilizing the temperature in a gear pump lubricated with material to be delivered.
When gear pumps equipped with slide bearings and lubricated by the material to be delivered are used to deliver polymers, the temperature of the material being delivered is of great significance because if, the temperature is too low, the viscosity is too high, and decomposition phenomena can occur at temperatures that are too high. Therefore, an attempt is made to keep the temperature of the medium being delivered within a certain range. This makes it possible significantly to increase the size of the operating window of the gear pump.
Hence, known heat exchangers are provided in the housing of the gear pump and in the shaft for temperature stabilization. The heat exchanger in the housing is connected to a heating assembly by a first system of lines and the heat exchanger in the shaft is connected to a cooling device by a second system of lines. The housing that gives off heat to the environment during operation is kept at a preset temperature by the heating assembly. The cooling assembly compensates for the heat which is generated and released by friction between the shaft and the bearing, thereby avoiding local overheating of the material being delivered.
The known method for temperature adjustment is, however, cumbersome and associated with correspondingly high costs.